JP2007224873A - Intake device and intake manifold for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce draft noise generated when a throttle valve 4 is abruptly opened without increasing an air flow resistance. <P>SOLUTION: The throttle valve 4 is arranged in an inlet passage 3 of a collector 1, and an expansion chamber 7 making a part of an inner wall surface in a circumference direction partially depressed in an outer circumference side is formed at a position at the slightly downstream side thereof. The expansion chamber 7 is provided corresponding to an area where high-speed flows passing through gaps of the throttle valve merge with each other and pressure is locally raised, and pressure energy is diffused by the expansion chamber 7 to reduce draft noise. A position in a direction inclined at 45° in relation to a rotary shaft 5 of the throttle valve 4 and at the side of one end edge 6a of a valve element 6 moving at the downstream side at a time of open action in a section of the intake passage becomes an optimal position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an intake device and an intake manifold for an internal combustion engine having a throttle valve, and more particularly to a technique for reducing abnormal noise when a throttle valve is suddenly opened.

  In an internal combustion engine equipped with a throttle valve, it is known that when the throttle valve is suddenly opened from the fully closed state, an airflow noise of “Suppa” or “Shu” is generated. When is made of synthetic resin, a more pronounced sound is generated, which is a problem.

In order to reduce this airflow noise, various measures have been taken conventionally as seen in Patent Documents 1 to 3, etc., and a grid-like rectifying member is attached to the intake passage to rectify the flow immediately after the throttle valve. On the other hand, it has been proposed to suppress noise associated with the merging of flows that have passed through the throttle valve by, for example, providing a convex portion immediately after the throttle valve to positively generate turbulence.
Japanese Patent Laid-Open No. 11-13500 JP-A-11-141416 JP 2002-155817 A

  However, any of these conventional noise reduction means is accompanied by an increase in pressure loss, and the greater the noise reduction effect, the greater the ventilation resistance. For example, if a grid-like rectifying member is arranged on the entire surface of the intake passage, a relatively large noise reduction effect can be obtained, but the ventilation resistance becomes very large. That is, the noise reduction effect and the ventilation resistance are in a trade-off relationship, and conventional noise reduction means cannot achieve noise reduction without increasing the ventilation resistance.

  In addition, when the intake manifold is made of synthetic resin, the conventional grid-like rectifying members that serve as noise reduction means cannot be molded integrally with the main body of the intake manifold. It becomes a factor of increase and complication of the assembly process.

  According to the present invention, a throttle valve in which a plate-shaped valve body rotates around a rotation shaft is provided in an intake passage, and one end edge of the valve body moves to the downstream side of the intake passage when the throttle valve is opened. In the intake device for an internal combustion engine in which the other end edge moves to the upstream side of the intake passage, the intake air flow that has passed through one end edge side of the valve body and the other end edge side downstream of the valve body An expansion chamber is provided on the inner wall surface of the intake passage in the vicinity of the longitudinal position where the intake air flow that has passed through is partially recessed in the outer circumferential side of the intake passage. It is said.

  Preferably, the expansion chamber is on the side where the one end edge of the valve element is located across the rotation shaft, and in the circumferential direction in a direction inclined by 45 ° with respect to the rotation shaft from the center of the intake passage It is provided in a part of the circumferential direction including the position.

  And in one aspect, it is provided in the range of 45 degrees which does not contain the direction along the said rotating shaft from the center of an intake passage, and the direction orthogonal to this rotating shaft.

  An intake manifold for an internal combustion engine according to the present invention includes a collector portion to which a plurality of branch portions are connected, a throttle chamber attachment flange to which a throttle chamber having a throttle valve is attached, and the collector portion from the throttle chamber attachment flange to the collector portion. An intake manifold made of synthetic resin, and an expansion chamber formed by partially hollowing the circumferential portion of the tubular portion on the outer peripheral side. Is formed.

  That is, the airflow noise when the throttle valve is suddenly opened is that the high-speed intake flow that has passed through one end of the valve body and the high-speed intake flow that has passed through the other end are It is thought that this is caused by the fact that they merge immediately after that to cause a local pressure increase, but by providing an expansion chamber appropriately at the position where such a local pressure increase occurs, the pressure energy is diffused and abnormal noise is generated. Is suppressed. As the position in the longitudinal direction of the intake passage in which the expansion chamber is provided, there is an appropriate position according to the aperture of the throttle valve, etc., and if it is excessively downstream (that is, the distance from the throttle valve is large), the effect is obtained. If it is small and excessively upstream (that is, the distance from the throttle valve is small), the noise may increase.

  Further, the position of the intake passage in the cross section of the intake passage is shifted to one side from the position of the rotary shaft due to the relationship with the inclination direction of the valve body at the time of opening, and more specifically, moves to the downstream side of the intake passage during the opening operation. Since the above-mentioned local pressure increase occurs at a position offset toward one edge of the valve body, the valve body rotates on the side where the one edge is located and from the center of the intake passage. When the expansion chamber is provided at a circumferential position in a direction inclined by 45 ° with respect to the axis, the noise reduction effect is most effectively obtained.

  In the configuration provided with the expansion chamber of the present invention, there is no increase in pressure loss, that is, ventilation resistance, because no grid-like rectification member or protrusion is interposed in the flow path through which the main flow of intake air flows.

  For example, when applied to a manifold made of a synthetic resin, an expansion chamber can be formed by partially denting a part of the peripheral wall of the tubular portion, so that it can be integrally formed as a part of the manifold. is there.

  According to the present invention, airflow noise when the throttle valve is suddenly opened can be suppressed without increasing the airflow resistance of the intake system. In addition, the configuration is simple without using a grid-like rectifying member or the like made of a separate part. For example, by integrally forming an expansion chamber in a synthetic resin manifold, the number of parts can be reduced and assembly can be simplified.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a structural explanatory view schematically showing the structure of an intake device of an internal combustion engine (for example, an in-line four-cylinder gasoline engine) according to the present invention. Are connected to an inlet passage 3 which is a part of the intake passage. The inlet passage 3 has a cylindrical shape with at least a part of a circular shape in section, and a throttle valve 4 is disposed in the cylindrical portion. The throttle valve 4 has a general butterfly valve type configuration. A rotary shaft 5 is provided so as to cross the center of the inlet passage 3 in the diametrical direction, and a disc-shaped valve body is provided on the rotary shaft 5. 6 is fixed and is opened and closed via an electric actuator or an accelerator wire (not shown). An air cleaner (not shown) is disposed on the upstream side of the throttle valve 4 in the intake passage.

  Further, as is well known, when the throttle valve 4 is fully closed, the one end edge 6a of the valve body 6 is positioned slightly downstream and the other end edge 6b is positioned relatively upstream, respectively. It has an inclined posture. During the opening operation, the one end edge 6a further moves to the downstream side from the fully closed position, and the other end edge 6b further moves to the upstream side.

  Here, in the present invention, at the position slightly downstream of the throttle valve 4 in the inlet passage 3, a part of the circumferential direction is partially recessed on the outer peripheral side on the inner wall surface of the inlet passage 3. An expansion chamber 7 is formed. By the expansion chamber 7, a local pressure increase when the throttle valve 4 is suddenly opened is alleviated, and airflow noise is suppressed. The shape of the expansion chamber 7 can be an arbitrary shape such as a simple rectangular shape or a cylindrical shape, but in this embodiment, for example, it is formed as a rectangular recess.

  Next, a more specific formation position of the expansion chamber 7 will be described.

  FIG. 2 illustrates a local pressure increase that causes airflow noise when the throttle valve 4 is open. The throttle valve 4 is closed and the negative pressure in the collector unit 1 is developed. When the throttle valve 4 suddenly opens, a high-speed intake flow flows through the gap 11 on the one end edge 6a side and the gap 12 on the other end edge 6b side of the valve body 6 as indicated by arrows V1 and V2, respectively. As a result of complicated merging on the downstream side of the throttle valve 4, a local pressure rise occurs in the region indicated by the symbol P. In particular, the gap 11 and the gap 12 have different flow velocities due to the inclination of the valve body 6 and the positions in the front-rear direction of the flow, so that the region P has a center line of the intake passage as shown in FIG. It is not located at the height position (that is, the height position corresponding to the rotation shaft 5), but is located below, that is, toward the one end edge 6a. The expansion chamber 7 needs to be located in the vicinity of the region P. Therefore, although the longitudinal direction of the intake passage varies depending on the diameter of the throttle valve 4 and the like, the vicinity of the position where the two intake flows V1 and V2 merge. For example, the vicinity of about several centimeters from the rotating shaft 5 to the downstream side is the optimum position. The position of the intake passage as viewed in cross section is 45 ° from the center of the intake passage with respect to the rotation shaft 5, particularly 45 ° on the side where the one end edge 6 a that moves downstream during the opening operation is located. The tilted direction is the optimum position. Thus, by providing the expansion chamber 7 at the optimum position corresponding to the region P where the local pressure rise occurs, the pressure energy is diffused and the actually generated noise is reduced. The expansion chamber 7 of the present invention does not narrow the passage cross-sectional area substantially or become a flow resistance unlike the conventional grid-like rectifying member, and therefore reduces airflow noise without increasing the airflow resistance. Can be achieved. Note that, as will be described later, if the expansion chamber 7 is in an inappropriate position, the air flow noise may be worsened.

  FIG. 3 summarizes the influence of parameters such as the position and size of the expansion chamber 7 and shows an example in which the present invention is applied to an intake device of an in-line four-cylinder gasoline engine having a displacement of 2000 cc. . Here, the sound pressure difference means that a microphone is disposed above the throttle valve 4 and collects airflow noise generated when the throttle valve 4 is changed from fully closed to fully open, and the expansion chamber 7 is not provided. The sound pressure difference when the noise in the configuration is used as a reference is shown. Therefore, minus means noise reduction, and plus means noise deterioration.

  Further, the distance L indicates the distance from the rotation shaft 5 of the throttle valve 4 to the center of the expansion chamber 7 as shown in FIG. As shown in FIG. 4B, the angle θ indicates the circumferential position of the center of the expansion chamber 7 in the passage cross section when the intake passage is viewed from the right side of FIG. 4A. The direction from which one end edge 6a is located is 0 °, and the angle from this point is shown. Accordingly, the directions of 90 ° and −90 ° are the axial directions of the rotating shaft 5. Further, the volume V indicates the volume of the expansion chamber 7. In this example, the expansion chamber 7 is formed in a rectangular shape.

  In the embodiment, the distance L is 80 mm, the angle θ is 45 °, and the volume V is 15 cc. Under such optimum parameters, a noise reduction effect of 3.4 dB was obtained.

  On the other hand, Comparative Example 1 is an example in which the distance L is shortened to 60 mm, that is, an example in which the expansion chamber 7 is arranged close to the throttle valve 4. In this case, airflow noise is worsened by 0.5 dB. I have. That is, if the expansion chamber 7 is excessively brought close to the throttle valve 4, the noise reduction effect cannot be obtained, and the noise worsens. Comparative Example 2 is an example in which the distance L is increased to 100 mm, that is, the expansion chamber 7 is arranged away from the throttle valve 4, and in this case, the noise reduction effect is reduced to 1.7 dB. Thus, it is clear from the comparison between the example and the comparative examples 1 and 2 that the distance L in the longitudinal direction has a certain optimum range.

  Comparative examples 3 and 4 are examples in which the angle θ for specifying the circumferential position where the expansion chamber 7 is formed is different from that of the example. Comparative Example 3 is an example in which θ is 90 ° and the expansion chamber 7 is provided in the direction along the rotation axis 5. In this case, the noise does not change. That is, the noise reduction effect by the expansion chamber 7 was not obtained. Comparative Example 4 is an example in which θ is 0 ° and the expansion chamber 7 is provided in the direction in which the one end edge 6a of the valve body 6 is located. In this case, the airflow noise was worsened by 1.4 dB. Thus, the best noise reduction effect is obtained in the vicinity of the 45 ° direction.

  Comparative Examples 5 and 6 are examples in which the volume V of the expansion chamber 7 is varied, and the depth (the dimension in the radial direction of the intake passage) is unchanged without changing the shape of the opening facing the intake passage of the expansion chamber 7. The volume V is changed by changing. Comparative Example 5 is an example in which the volume V is 5 cc, and the noise reduction effect is 2.9 dB. Comparative Example 6 is an example in which the volume V is 30 cc, and the noise reduction effect is 3.2 dB. Therefore, it can be said that the size of the volume V hardly affects the noise reduction effect.

  Next, FIGS. 5 to 8 show the configuration of a specific intake manifold according to the present invention. The intake manifold is a synthetic resin manifold for an in-line four-cylinder gasoline engine, and a cylinder head mounting flange 21 that is attached to a side surface of a cylinder head (not shown), and each tip is connected to the cylinder head mounting flange 21. The four branch portions 22, an elongated volume chamber to which the base ends of the four branch portions 22 are connected, that is, the collector portion 23, and from the one end portion of the collector portion 23 along the longitudinal direction of the collector portion 23. A substantially cylindrical tubular portion 24 that extends, and a substantially square throttle chamber mounting flange 25 provided at the tip of the tubular portion 24 are provided. A throttle chamber (not shown) having a throttle valve is attached to the throttle chamber mounting flange 25, and an intake passage in the throttle chamber that is opened and closed by the throttle valve continues to the intake passage in the tubular portion 24 without a step. . The branch portion 22 has a large curved shape so as to extend upward from a cylinder head mounting flange 21 attached to one side surface of the cylinder head and to extend across the cylinder head. The collector portion 23 extends elongated along the cylinder row direction, and the flow path center line of the tubular portion 24 continuing to one end thereof is substantially along the cylinder row direction. The flange surface of the throttle chamber mounting flange 25 is substantially orthogonal to the flow path center line of the tubular portion 24. Therefore, the throttle chamber, the tubular portion 24, and the collector portion 23 are arranged on a straight line.

  Here, an expansion chamber 26 is formed integrally with a part of the peripheral wall of the tubular portion 24 by partially recessing a part in the circumferential direction toward the outer peripheral side. The expansion chamber 26 has a simple rectangular shape, and is molded simultaneously with injection molding when the tubular portion 24 is divided into two. By aligning the depth direction of the concave portion of the expansion chamber 26 with the mold opening direction of the mold, it is possible to mold the mold integrally without using a complicated core or the like.

  Although the throttle valve is not shown in the drawing, as described above, the expansion chamber 26 is provided in a predetermined direction inclined by 45 ° with respect to the rotation axis of the throttle valve, and from the rotation axis of the throttle valve. The position is set so as to be the predetermined distance downstream side.

  As described above, according to the present invention, air flow noise when the throttle valve is suddenly opened can be effectively reduced with a simple configuration in which the expansion chamber 26 is simply formed in the intake manifold made of synthetic resin. A separate member such as a rectifying member is not required, so that the number of parts can be reduced and the number of assembly steps can be minimized.

BRIEF DESCRIPTION OF THE DRAWINGS The structure explanatory drawing which showed schematically the structure of the intake device which concerns on this invention. Explanatory drawing of the local pressure rise when a throttle valve opens. Explanatory drawing which summarized the Example and comparative example which changed the parameter of the expansion chamber. Explanatory drawing of each parameter. The top view of the synthetic resin intake manifold which concerns on this invention. Similarly bottom view. Similarly side view. The enlarged view of the principal part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Collector part 2 ... Branch part 3 ... Inlet passage 4 ... Throttle valve 5 ... Rotating shaft 6 ... Valve body 7 ... Expansion chamber 26 ... Expansion chamber

Claims (4)

  A throttle valve in which a plate-like valve body rotates around a rotation shaft is provided in the intake passage, and when the throttle valve is opened, one end edge of the valve body moves to the downstream side of the intake passage, and the other end In an intake system for an internal combustion engine in which an edge moves to the upstream side of the intake passage, the intake air flow that has passed through one end edge side of the valve body and the intake air that has passed through the other end edge side downstream of the valve body An internal combustion engine characterized in that an expansion chamber is provided on the inner wall surface of the intake passage near a longitudinal position where the flow merges, and a part of the circumferential direction of the intake passage is partially recessed toward the outer peripheral side. Inhalation device.   On the side where the one end edge of the valve body is located across the rotation shaft, and in a part of the circumferential direction including a circumferential position in a direction inclined by 45 ° with respect to the rotation shaft from the center of the intake passage 2. The intake device for an internal combustion engine according to claim 1, wherein the expansion chamber is provided.   3. The internal combustion engine according to claim 2, wherein the expansion chamber is provided within a range of 45 ° not including a direction along the rotation axis from a center of the intake passage and a direction orthogonal to the rotation axis. Inhalation device. A collector portion to which a plurality of branch portions are connected; a throttle chamber attachment flange to which a throttle chamber having a throttle valve is attached; and a substantially cylindrical tubular portion extending from the throttle chamber attachment flange to the collector portion. An intake manifold for an internal combustion engine, wherein an expansion chamber is formed integrally with a peripheral wall of the tubular portion and a part of the circumferential direction is partially recessed toward the outer peripheral side. Manifold.

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